A military parade in southern Iraq, during which equipment that would be used in the fight for Mosul was displayed. (photo: حيدر الحمداني)

Over the past few days anti-extremist forces have reached the outskirts of Mosul. There are a number of factors that those fighting the extremist group known as the Islamic State, who have controlled the northern Iraqi city for over two years, will be considering, as they enter the city proper.

Firstly, the direction the military campaign, currently being waged, takes will depend very much on the city’s geography. More than half of the city is residential neighbourhoods and the rest is industrial or includes public institutions, government buildings and markets, some of which have been being used by the IS group.

The Tigris River passes through Mosul and locals usually refer to the cityscape as being on the left or right bank, or left or right side, of the river, with the left bank being Mosul’s north-eastern side and the right being the city’s south-west.

Mosul also has forests and the IS group established training camps in these areas at an early stage of their occupation of the city. The forest has been important for the extremist group as it has been possible to hide here from the reconnaissance flights criss-crossing the city regularly as well as air strikes. The militants may well use the river and the forest as a natural barrier to stop their opponents from advancing.

This is exactly what the IS group wants, to drag the opposition into the city, and especially into the more crowded neighbourhoods.

The IS group’s heart lies on the right bank of the Tigris River; this area is of strategic importance as it connects the province of Ninawa, of which Mosul is the capital, to Syria. In fact, this area has been a stronghold for extremists in Mosul since 2006. Both the Iraqi army and the US army tried to eliminate local extremists from here and failed. And in fact, the anti-extremist forces have left this desert corridor looking toward Syria open. Unlike the rest of the city, this side of Mosul has been left uncontrolled, in the hopes that the extremists will see themselves out.

This side of the city also contains the city centre and military sites such as the Ghazalani military base, which sits in an important spot by the city’s southern entrance, as well as the airport, train station and a major industrial area, which has been used by the IS group to manufacture bombs.

The number of civilians inside the city is also problematic. Estimates about how many people are trapped inside the city vary, anything from just below a million to 2 million – the larger figure has come about, locals say, because of an influx of displaced Iraqis from areas surrounding Mosul and further afield, such as Anbar and Salahaddin, entering the metropolis.

The city’s population is itself divided. On the left bank, population density is lower because many of the buildings here are new and modern. The houses were distributed to civil servants and retired civil servants over the past six decades or so. On the right bank, it is a different story with a high-density population and houses built close to one another in an old city. Alleyways are narrow and cars may not be able to drive down many of them; this will doubtless hamper the movement of military vehicles when the time comes.

There are those who believe that this is exactly what the IS group wants, to drag the opposition into the city, and especially into the more crowded and dense right bank neighbourhoods.

There are also Mosul’s diverse demographics to consider. There is more of what may best be described as a “fighting spirit” on the right bank of the city, due to the make-up of the residential population there, which tends to include more lower-income locals and people who originally come from villages outside the city. By all accounts, the middle-class residents on the left bank are less inclined to fight.

The majority of Mosul’s residents are Sunni Muslim Arabs. They are estimated to make up over three-quarters of the city’s people. During the past two years, as other Mosul minorities – such as Christians, Shabaks, Kurds and Turkmen – were forced out of the city by the extremists, that percentage has come closer to 90 percent.

Non-Arabs were living mostly on the city’s left bank, which is geographically closer to the nearby semi-autonomous region of Iraqi Kurdistan. The right bank has been the recipient of waves of displaced from Arab villages to the west and south of the city. Most recently there was an influx from the Qayyarah district.

Mosul’s mayor, Hussein Ali Hajem, who is working from outside the city, has said that 20,000 villagers from towns surrounding Mosul were forced to come into the city by the IS group, as the Iraqi army advanced toward them.

Any successful military plan would split Mosul into sectors and then attempt to control each sector, one by one. This will be difficult, especially as the IS group has had experience with urban warfare. There are already reports of street-by-street battles. Urban warfare will also impact on the effectiveness of air support, which has been decisive in more open areas.

The battle for Mosul is necessary and it will be complicated and difficult for the people of Mosul to bear. And as the old Arabic saying goes, the calculations made on the wheat field may differ from the accounting on the threshing floor.